Defending his client Alexander Williams asked for psychological reports to be compiled by medical specialists.

He continued: 'There are 25 offences on the indictment of which there are 23 guilty pleas to the serious specified offences.'

A pre-sentence report has already been produced and the teacher will have to sign the Sexual Offenders Register.

Judge Gordon Risius, who remanded the teacher in custody, said: 'The pleas of guilty mean the signing of the Sexual Offences Register is automatic but I acknowledge the length of time will depend on the sentence.'

Sentencing will now take place on Friday, December 10.

A Section 39 order under the Children and Young Person Act 1933 has temporarily been made by Judge Risius.

It prevents the name of the school or anything that could lead to the identification of the victims being made public.

'I have to weigh up the balance of open reporting and the need to protect the children's vulnerability,' he said.

Judge Risius will make a formal decision about the order tomorrow.

After the hearing, many of the families of the victims' said they were too upset to speak anonymously about the abuse.

But one father did tell waiting reporters: 'We're still trying to come to terms with what's happened and take it all in.

'We're all devastated by this.'

Detective Chief Inspector Paul Gration, leading the investigation for Thames Valley Police, said: 'I am relieved that the victims in this case have not been put through the ordeal of a full trial.

'This investigation has been difficult enough for them and I would like to personally thank them for their courage and bravery in coming forward and helping the police with this investigation.

'I hope that with time and support they are able to find some closure on this matter.

'Offences of this type are deplorable by their very nature and Thames Valley Police, supported by our partners, will relentlessly pursue those that commit this sort of crime.'